This invention relates to a printer controller which generates character patterns from character codes for printing, and particularly to a printer controller which is capable of printing characters in variable character size.
In the conventional printer controller with the ability of printing characters in variable size, lines of characters to be printed and the vertical dimension of the lines of characters (will be termed "line size" hereinafter) are memorized. The stored lines of characters are printed in the specified line sizes by enlarging or reducing original character patterns retrieved from the character pattern memory and by writing the reformed character patterns into a page memory 8 which corresponds to a page of print paper as shown in FIG. 1. The term "character" in this specification includes a Kanji character, an alphanumeric character, a symbolic character, etc.
Fast setting of character patterns in the page memory 8 in response to input character codes requires a line buffer memory which is made up of a relatively expersive fast-access memory device. A character pattern is once held in the line buffer memory and, after adjustment of character position, the contents of the line buffer memory are transferred to the page memory. The line buffer memory needs to have a line size which covers the maximum possible line size (e.g., shown by Q in FIG. 1), and therefore the line buffer memory has an increased capacity, namely an increased cost, as characters are printed in a larger line size. This type of printer controller is disclosed, for example, in JP-A-No.-55-34725.